The following extended example may make the usage clearer; <?php// Create two timezone objects, one for Taipei (Taiwan) and one for// Tokyo (Japan)$dateTimeZoneTaipei = new DateTimeZone("Asia/Taipei");$dateTimeZoneJapan = new DateTimeZone("Asia/Tokyo");

// Create two DateTime objects that will contain the same Unix timestamp, but// have different timezones attached to them.$dateTimeTaipei = new DateTime("now", $dateTimeZoneTaipei);$dateTimeJapan = new DateTime("now", $dateTimeZoneJapan);

// NOTE: $dateTimeJapan is not used further in this example

// Calculate the GMT offset for the date/time contained in the $dateTimeTaipei// object, but using the timezone rules as defined for Tokyo// ($dateTimeZoneJapan).$timeOffset = $dateTimeZoneJapan->getOffset($dateTimeTaipei);

// Should show int(32400) (for dates after Sat Sep 8 01:00:00 1951 JST).print("Number of seconds Japan is ahead of GMT at the specific time: ");var_dump($timeOffset);

print("<br />Number of seconds Taipei is ahead of GMT at the specific time: ");var_dump($dateTimeZoneTaipei->getOffset($dateTimeTaipei));

print("<br />Number of seconds Japan is ahead of Taipei at the specific time: ");var_dump($dateTimeZoneJapan->getOffset($dateTimeTaipei) -$dateTimeZoneTaipei->getOffset($dateTimeTaipei));

print("<hr />");

?>

Number of seconds Japan is ahead of GMT at the specific time: int(32400)Number of seconds Taipei is ahead of GMT at the specific time: int(28800)Number of seconds Japan is ahead of Taipei at the specific time: int(3600)